* Cleanup some comments and introduce a helper to check if the configuration is HTML5.
* Allow b, i, u and s tags in HTML 5 as they are not obsolete in HTML 5 (and i is in fact frequently used for icons).
* Add XWikiHTML5TagProvider to fix svg and style tag handling.
* Fix class fan-out complexity in DefaultHTMLCleaner by not using the CleanerTransformations class but only our subclass.